Related art multi-lumen catheters are desirable for various treatment applications such as hemodialysis where fluid extraction and infusion occur simultaneously. These related art multi-lumen catheters provide a single catheter application having multiple lumen channels, each channel supporting independent flow, thus, precluding the need for inserting multiple catheters or multiple-catheter assemblies. Further, because a patient might require frequent dialysis, often only days apart, securing placement of the catheter for extended periods of time may be required. Extended placement, however, requires extreme catheter flexibility to avoid damage to the blood vessel and to permit the catheter to move in the blood flow in order to minimize the possibility of the catheter remaining in contact with the wall of the vessel for prolonged periods, otherwise causing undue pressure thereon. Related art stylets also have a tendency to snag interior surfaces of a blood vessel, thereby unduly damaging the blood vessel.
An example of a related art multi-lumen catheter includes an elongated tubular body extending to a distal end. The tubular body has a first and a second lumen with a septum disposed therebetween. The tubular body includes a first wall that defines the first lumen and a second wall that defines the second lumen. A portion of the septum extends distally beyond the first lumen and the second lumen. The first wall includes a first wall extension that extends distally beyond the first lumen and is spaced apart from the portion of the septum. The first wall extension defines a concave surface facing the portion of the septum. Alternatively, the catheter includes a tip with spiraled configuration. The catheter may also include a third lumen.
Another example of a related art multi-lumen catheter includes a tubular body having a proximal end and a distal end. The body includes a first lumen and a second lumen with a septum disposed therebetween. The proximal end includes a valve and a hub that are integral with the body. The hub includes a first conduit and a second conduit. The valve includes a first port and a second port that are rotatable, about a longitudinal axis of the body, to establish fluid communication between the lumens and the conduits. The distal end of the tubular body is configured for insertion. The conduits are connectable to a medical apparatus.
Yet another example of a related art multi-lumen catheter includes an elongated tubular body extending to a distal end. The tubular body has a first and a second lumen with a septum disposed therebetween and has a first wall that defines the first lumen and a second wall that defines the second lumen. A portion of the septum extends distally beyond the first lumen and the second lumen. The first wall includes a first wall extension that extends distally beyond the first lumen and is spaced apart from the portion of the septum. The first wall extension defines a concave surface facing the portion of the septum. Alternatively, the septum has a septum extension that extends distally beyond the first lumen and the second lumen; and the septum extension defines a first planar surface and an opposing second planar surface.
Unfortunately, these related art catheters introduce insertion difficulties, including a relative inflexibility thereof. For example, simply advancing the catheter over a guide-wire is very difficult in the related art, since the catheter has a tendency to buckle during disposition through the blood vessel wall as well as during further disposition into the blood vessel to the desired location. Flexible catheters present additional difficulties associated with subcutaneous tunneling and placement. Related art insertion methods and assemblies attempt to overcome, or at least mitigate, these insertion difficulties by temporarily stiffening the catheter during the insertion process.
For example, one related art method involves temporarily inserting a rigid tubular applicator into one of the lumens. This permits the stiffened catheter/applicator assembly to be passed over a guide-wire into a desired position, at which point the applicator can be removed. For example, U.S. Pat. No. 5,405,341 attempts to solve the problem with a single rigid applicator that is designed for insertion into one lumen but also passes through a portion of the second lumen (at the distal end of the instrument) to effectively stiffen the two lumens of the catheter together during insertion. This related art approach is cumbersome, at best, and presents additional difficulties in maneuvering the instrument. Further, this temporary rigid applicator approach is poorly suited for placement of a catheter having a split at its distal end into two or more separate lumens, e.g., to further isolate a fluid extraction lumen from a return infusion lumen, because only one tip can be secured. Hence, a need exists for better and more effective apparatuses, systems, and methods for inserting flexible catheters into blood vessels.